Given a string, determine if it is a palindrome, considering only alphanumeric characters and ignoring cases. For example,"A man, a plan, a canal: Panama" is a palindrome."race a car" is not a palindrome. Note:Have you consider that th…

Given a string, determine if it is a palindrome, considering only alphanumeric characters and ignoring cases. For example, "A man, a plan, a canal: Panama" is a palindrome. "race a car" is not a palindrome. Note: Have you consider that…

Given a string, determine if it is a palindrome, considering only alphanumeric characters and ignoring cases. For example,"A man, a plan, a canal: Panama"is a palindrome."race a car"is not a palindrome. Note: Have you consider that the…

Given a string, determine if it is a palindrome, considering only alphanumeric characters and ignoring cases. Note: For the purpose of this problem, we define empty string as valid palindrome. Example 1: Input: "A man, a plan, a canal: Panama" O…

Given a string, determine if it is a palindrome, considering only alphanumeric characters and ignoring cases. Notice Have you consider that the string might be empty? This is a good question to ask during an interview. For the purpose of this problem…

给定一个字符串,确定它是否是回文,只考虑字母数字字符和忽略大小写.例如:"A man, a plan, a canal: Panama" 是回文字符串."race a car" 不是回文字符串.注意:你有考虑过这个字符串可能是空的吗? 在面试中这是一个很好的问题.针对此题目,我们将空字符串定义为有效的回文字符串.详见:https://leetcode.com/problems/valid-palindrome/description/ Java实现: class S…

Given a string, determine if it is a palindrome, considering only alphanumeric characters and ignoring cases. For example,"A man, a plan, a canal: Panama" is a palindrome."race a car" is not a palindrome. Note:Have you consider that th…

class Solution { public: bool isPalindrome(string s) { if(s=="") return true; ) return true; //单个字符,对称 char *p,*q; p=&s[]; //p指向开头 q=&s[s.length()-]; //q指向末尾 while(p!=q){ //测试字符串里是否有字母或数字,若没有,则立刻返回 '&&*p<'A') || (*p>'Z'&…

Given a string s, you are allowed to convert it to a palindrome by adding characters in front of it. Find and return the shortest palindrome you can find by performing this transformation. Example 1: Input: "aacecaaa" Output: "aaacecaaa&quo…

题目: 有效回文串 给定一个字符串,判断其是否为一个回文串.只包含字母和数字,忽略大小写. 样例 "A man, a plan, a canal: Panama" 是一个回文. "race a car" 不是一个回文. 注意 你是否考虑过,字符串有可能是空字符串?这是面试过程中,面试官常常会问的问题. 在这个题目中,我们将空字符串判定为有效回文. 挑战 O(n) 时间复杂度,且不占用额外空间. 解题: 去除非有效字符后,整体是个回文串,两边查找,利用快速排序的思想,…